The Eagles’ guitar sound may be best identified with the ferocious “Hotel California” fretwork of Joe Walsh and Don Felder, but Glenn Frey’s playing was also key to the group’s output. Vince Gill, himself an ace guitarist who has turned in solos for artists as varied as Alice Cooper and the Doobie Brothers, says Frey the musician was underrated.

“He was a world-class guitar player. For a long time, Don Felder and Joe were front and center taking the lead role, but I don’t think a lot of people realize that all that soulful guitar playing was Glenn,” Gill tells Rolling Stone Country of Frey, who died Monday at age 67.

Gill recorded the band’s “I Can’t Tell You Why” for the 1993 Eagles tribute album Common Thread, choosing to add saxophone, a hallmark of Frey’s Eighties solo work, to his version. “I don’t know why I chose to put sax on it — it’d have been fun to play those slippery guitar parts that Glenn played. That’s a very restrained solo in ‘I Can’t Tell You Why,’” he says.

Although the Eagles were most known for a laid-back brand of California country-rock, Gill says they were just as much a soul and rock & roll band. Thanks in part to Frey, who was raised in Detroit.

“Most people hear him sing ‘Lyin’ Eyes’ or ‘New Kid in Town,’ but he was a Detroit boy. He knew what soul music was,” says Gill. “He knew what rock & roll really was, probably more than anybody else in that band until Joe Walsh comes along. You have to have a leader, and he was a great one.”

Gill first met Frey and the Eagles during the group’s Long Run Tour, and became fast friends with the singer-guitarist, playing golf together, using Frey’s Lakers tickets and, in 2007, introducing the band when they performed on the CMA Awards.

“They said, ‘We’ll play, but we want Vince to introduce us.’ So I’ve been connected to them for 35-plus years,” he says. “I think that’s one of the most important bands ever, just from the legacy of the songs.”

Gill is just one of many country artists who have paid their respects to Frey. Travis Tritt, who covered “Take It Easy” for Common Thread and helped reunite the band for the song’s video, told Rolling Stone Country that Frey’s work ethic was unmatched.

“If you look at the entire catalog of all the things that the Eagles did for all those years, not to mention the things that Glenn did in his solo career, it’s always just top-notch,” he says. “It was an inspiration just to be around him and to listen to the songs that he did both with the Eagles and on solo projects and just know that he was one of the greats of our time.”